Method format_signed

include/fmt/format.h:4193–4200

  template <typename Int>
  FMT_CONSTEXPR20 auto format_signed(Int value) -> char* {
    auto abs_value = static_cast<detail::uint32_or_64_or_128_t<Int>>(value);
    bool negative = value < 0;
    if (negative) abs_value = 0 - abs_value;
    auto begin = format_unsigned(abs_value);
    if (negative) *--begin = '-';
    return begin;
  }

 public:
  FMT_CONSTEXPR20 explicit format_int(int value) : str_(format_signed(value)) {}